function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}
function changeMainVision()
{
	main = new Array('index_main_vision_c4.jpg','index_main_vision_c6.jpg','index_main_vision_c2.jpg','index_main_vision_picasso.jpg','index_main_vision_triomphe.jpg');
	num= Math.round(Math.random() * 6);

	if(num==0){num=num+1;}
	if(num==6){num=num-1;}
	document.getElementById("main_images").innerHTML = '<img src="./resources/images/'+ main[num-1] +'"  alt="main vision" />'	
}